In recent years, a liquid crystal display device (liquid crystal display (LCD)) has been widely used to provide a display monitor for a liquid crystal television receiver, a laptop, a car navigation device and the like. This type of liquid crystal display device is classified into various types of display modes (systems) on the basis of molecular arrangement (orientation) of respective liquid crystal molecules contained in a liquid crystal layer sandwiched between a pair of substrates. A well-known display mode is a twisted nematic (TN) mode, for example, where liquid crystal molecules are twistedly oriented in a voltage non-application state. In the TN mode, a liquid crystal molecule has a feature of positive dielectric anisotropy, i.e., a feature that a dielectric constant of liquid crystal molecules in the major axis direction is larger than in the minor axis direction. Accordingly, there is produced such a structure that the liquid crystal molecules are aligned in directions perpendicular to a substrate plane with sequential rotation of orientation directions of the liquid crystal molecules in a plane parallel with the substrate plane.
On the other hand, currently attracting attention is a vertical alignment (VA) mode where liquid crystal molecules are oriented perpendicularly to the substrate plane in a voltage non-application state. In the VA mode, a liquid crystal molecule has a feature of negative dielectric anisotropy, i.e., a feature that a dielectric constant of liquid crystal molecules in the major axis direction is smaller than in the minor axis direction. In this case, a larger viewing angle than that of the TN mode is realizable.
According to the liquid crystal display device in the foregoing VA mode, liquid crystal molecules oriented in the direction perpendicular to the substrate are responded in a manner falling in directions parallel with the substrate on the basis of negative dielectric anisotropy when voltage is applied to the liquid crystal display device. As a result, light is allowed to pass through the liquid crystal display device. However, the liquid crystal molecules oriented in the directions perpendicular to the substrate fall in random directions. This randomness of the falling directions may cause disorder of the orientation of the liquid crystal molecules, and deteriorate response characteristics to voltage.
Accordingly, there have been proposed various methods for regulating the orientation of the liquid crystal molecules during voltage application. For example, currently proposed are a multi-domain vertical alignment (MVA) system, a patterned vertical alignment (PVA) system, and a method using light orientation film (e.g. see Japanese Patent Application Laid-Open No. 5-232473). The MVA system realizes a large viewing angle under orientation control by using slits and ribs (projections). In addition to the foregoing examples, recently proposed is a structure (called fine slit structure) which includes a first electrode (more specifically, pixel electrode) formed on one substrate and provided with a plurality of fine slits, and a second electrode (more specifically, counter electrode) formed on the other substrate and provided as a so-called solid electrode without slits (e.g. see Japanese Patent Application Laid-Open No. 2002-357830).
Further known is a lateral electric field driving type liquid crystal display device, such as a transmission type in-plane-switching (IPS) system liquid crystal display device, for example. In addition, in case of a so-called normally black type, the direction of the polarization axis of one polarizing plate and a director become substantially the same in a state of non-application of an electric field to the liquid crystal layer, and form an angle of substantially 45 degrees in a state of application of an electric field to the liquid crystal layer. In the state of non-application of an electric field to the liquid crystal layer, light entering an entrance side polarizing plate reaches an exit side polarizing plate with substantially no retardation by the liquid crystal layer, and is absorbed by the exit side polarizing plate (black display state). Accordingly, a state substantially equivalent to an ideal crossed-Nichol state without interposition of a liquid crystal layer is realizable in a black display state. On the other hand, in a state of application of an electric field to the liquid crystal layer, the director and linearly polarized light having passed through the entrance side polarizing plate form an angle of substantially 45 degrees. In this case, the liquid crystal layer functions as a half-wave plate, and rotates an oscillation direction of the linearly polarized light through 90 degrees. As a result, the light having passed through the liquid crystal layer passes through the exit side polarizing plate (white display state). The first electrode and the second electrode are formed on the same substrate, and form a comb teeth structure facing each other and alternately combined.